Preoperative Visceral Adiposity and Muscularity Predict Poor Outcomes after Hepatectomy for Hepatocellular Carcinoma

Abstract

Objective: Visceral adiposity, defined as a high visceral-to-subcutaneous adipose tissue area ratio (VSR), has been shown to be associated with poor outcomes in several cancers. However, in the surgical field, the significance of visceral adiposity remains controversial. The present study investigated the impact of visceral adiposity as well as sarcopenic factors (low muscularity) on outcomes in patients undergoing hepatectomy for hepatocellular carcinoma (HCC).

Patients and methods: This retrospective study analyzed data from 606 patients undergoing hepatectomy for HCC at our institution between April 2005 and March 2016. Using preoperative plain computed tomography imaging at the level of the third lumbar vertebra, visceral adiposity, skeletal muscle mass, and muscle quality were evaluated by the VSR, skeletal muscle mass index (SMI), and intramuscular adipose tissue content (IMAC), respectively. The impact of these parameters on outcomes after hepatectomy for HCC was analyzed.

Results: The overall survival rate was significantly lower among patients with a high VSR (p < 0.001) than among patients with a normal VSR. Similarly, the recurrence-free survival rate was significantly lower among patients with a high VSR (p = 0.016). A high VSR, low SMI, and high IMAC contributed to an increased risk of death (p < 0.001) and HCC recurrence (p < 0.001) in an additive manner. Multivariate analysis showed that not only preoperative low muscularity but also visceral adiposity was a significant risk factor for mortality (hazard ratio [HR] = 1.566, p < 0.001) and HCC recurrence (HR = 1.329, p = 0.020) after hepatectomy for HCC.

Conclusions: Preoperative visceral adiposity, as well as low muscularity, was closely related to poor outcomes after hepatectomy for HCC. It is crucial to establish a new strategy including perioperative nutritional interventions with rehabilitation for better outcomes after hepatectomy for HCC.

Keywords: Hepatocellular carcinoma; Intramuscular adipose tissue content; Sarcopenia; Skeletal muscle mass index; Visceral adiposity; Visceral-to-subcutaneous adipose tissue area ratio.

Fig. 1

Cross-sectional CT images at the level of the third lumbar vertebra. a Subcutaneous adipose tissue areas are identified and quantified using CT attenuation values of −190 to −30 HU. b Visceral adipose tissue areas are quantified using attenuation values of −150 to −50 HU. c Skeletal muscle areas are quantified using a CT attenuation value of −29 to 150 HU. d CT attenuation values of subfascial muscular tissue in the multifidus muscle and subcutaneous fat (4 small circles) are examined to calculate the intramuscular adipose tissue content. CT, computed tomography; HU, Hounsfield unit.

Fig. 2

OS rates among patients classified according to body composition variables. a The OS rate after hepatectomy for hepatocellular carcinoma was significantly lower among the patients with a high VSR (n = 252) than among the patients with a normal VSR (n = 354; p < 0.001). b The OS rate was significantly lower among the patients with a low SMI (n = 84) than among the patients with a normal SMI (n = 522; p = 0.012). c The OS rate was significantly lower among the patients with a high IMAC (n = 258) than among the patients with a normal IMAC (n = 348; p < 0.001). OS, overall survival; VSR, visceral-to-subcutaneous adipose tissue area ratio; SMI, skeletal muscle mass index; IMAC, intramuscular adipose tissue content.

Fig. 3

RFS rates among patients classified according to body composition variables. a The RFS rate after hepatectomy for hepatocellular carcinoma was significantly lower among the patients with a high VSR than among the patients with a normal VSR (p = 0.016). b The RFS rate was significantly lower among the patients with a low SMI than among the patients with a normal SMI (p = 0.009). c The RFS rate was significantly lower among the patients with a high IMAC than among the patients with a normal IMAC (p = 0.047). RFS, recurrence-free survival; VSR, visceral-to-subcutaneous adipose tissue area ratio; SMI, skeletal muscle mass index; IMAC, intramuscular adipose tissue content.

Fig. 4

OS and RFS rates among patients classified by the number of body composition variables. The OS (a) and RFS (b) rates after hepatectomy for hepatocellular carcinoma decreased significantly with an increasing number of prognostic body composition factors (high visceral-to-subcutaneous adipose tissue area ratio, low skeletal muscle mass index, and high intramuscular adipose tissue content) (p < 0.001 and p < 0.001, respectively). OS, overall survival; RFS, recurrence-free survival.